2nd Gen Non-Engine/Transmission NEED HELP! Tach/speedo/OD/Alt. problems

[Evest]

My tach and speedo don't work. The battery gauge reads about 12. 5 and I have no OD. I first replaced the alternator( had it tested and was failing)..... Didn't help. Replaced the ESS..... Took it for a drive and the battery gauge reads 14. 8 so the charging problem is fixed. After the engine warmed up the tach started moving but it's sporadic. Jumping all over the place. Still no speedo or OD. So I replaced the VSS on the transfer case at the rear of the transmission. Still no speedo or OD. I unplugged the ESS and drove around the block... ... Battery gauge is low no tach but the speedo works and transmission shifts to OD. I Plugged the ESS back in and back to good charging crazy jumping around tach but no speedo or OD. I went down the street to talk to the people at the parts store about maybe a different sensor. They were no help. Jumped in the truck and started driving through the parking lot. The speedo started jumping around like the tach. A Few blocks down the road it quit completely again. I am absolutely stumped! What is going on? Why does the speedo work when the Engine Speed Sensor is unplugged and doesn't when it is? If anyone knows what is going on please help me! My dodge is my only vehicle and I use it to pull work trailers on a daily basis not to mention getting to everywhere. I NEED my truck to work!!!

 

[n7gxz]

I would change out the crankshaft position sensor. Should be on the driver's side near the starter.

Kevin

 

[mwilson]

My tach and speedo don't work. The battery gauge reads about 12. 5 and I have no OD. I first replaced the alternator( had it tested and was failing)..... Didn't help. Replaced the ESS..... Took it for a drive and the battery gauge reads 14. 8 so the charging problem is fixed. After the engine warmed up the tach started moving but it's sporadic. Jumping all over the place. Still no speedo or OD. So I replaced the VSS on the transfer case at the rear of the transmission. Still no speedo or OD. I unplugged the ESS and drove around the block... ... Battery gauge is low no tach but the speedo works and transmission shifts to OD. I Plugged the ESS back in and back to good charging crazy jumping around tach but no speedo or OD. I went down the street to talk to the people at the parts store about maybe a different sensor. They were no help. Jumped in the truck and started driving through the parking lot. The speedo started jumping around like the tach. A Few blocks down the road it quit completely again. I am absolutely stumped! What is going on? Why does the speedo work when the Engine Speed Sensor is unplugged and doesn't when it is? If anyone knows what is going on please help me! My dodge is my only vehicle and I use it to pull work trailers on a daily basis not to mention getting to everywhere. I NEED my truck to work!!!

A fellow TDR member went through a very similar situation a month or so ago. He had a blown fuse.



I do not have time to search it right now, maybe someone else will jump in. I can't remember the title of his thread, it was either in 911 or the second gen forum.



Mike.

 

[Moe]

I had the exact same problem. Disc battery grounds and pull the starter. Replace the crank sensor. Works like a charm. Moe

 

[mwilson]

I had the exact same problem. Disc battery grounds and pull the starter. Replace the crank sensor. Works like a charm. Moe

If Moe's suggestion does not work I just found the other thread. The only thing different was his fuel solenoid went out as well. Do you still have one or has it been converted to a cable style??



Thread here...

https://www.turbodieselregister.com/forums/showthread.php?240264-97-with-engine-electrical-problems



Mike.

 

[Evest]

To my knowledge the Engine Speed Sensor (ESS) that I replaced IS the Crank Position Sensor just different terminology. When I checked around the local parts stores for the ESS I couldn't find it. They kept telling me it doesn't exist. In my book it says ESS at the parts stores its listed as the CPS. Same part. So thanks but that sensor is the first thing I did. That and the alternator. Any other ideas?

 

[Evest]

Is there a different sensor that I have to take off the starter to get to that I don't know about? I'm going off the book I have and it doesn't say anything about another sensor.

 

[mwilson]

To my knowledge the Engine Speed Sensor (ESS) that I replaced IS the Crank Position Sensor just different terminology. When I checked around the local parts stores for the ESS I couldn't find it. They kept telling me it doesn't exist. In my book it says ESS at the parts stores its listed as the CPS. Same part. So thanks but that sensor is the first thing I did. That and the alternator. Any other ideas?

Yes, ESS, CPS same thing. Did you read all the way through the thread that I posted???



Mike.

 

[Evest]

Yes I read through that thread. My truck starts just fine. It's runs and idles. Doesn't make any strange noises. It will drive down the road and shift 1-2-3 just not OD

 

[Evest]

In the last few days... ... New alternator, ESS, and VSS. I took the dash apart pulled out the cluster checked all the wiring and connections. The new ESS did kinda make the tach work its moves at least. Putting in the VSS didn't help anything. The thing that confuses me the most is that the speedo works if I unplug the ESS. Plug it back in and no speedo. Is there a way to test the sensor to make sure it's good? I can take it off in about 60 seconds its easy. Two nuts and two bolts unplug it and done.

 

[cerberusiam]

As a guess, you either have some bad connections to the SBEC or it is hosed. Start by checking and scraping all your ground and battery connections to see if that will help.

The OD can be made to work with a simple switch i needed.

 

[LNaugle]

We found a spot in the wiring harness at the back of the head drivers side that one of the wires had rubbed through and was grounding out.....

 

[JLandry]

Evest,



All of the problems and symptoms you're describing do have something in common... the PCM (Powertrain Control Module). Information displayed by the instrument cluster comes from the PCM. The PCM also controls the alternator charging rate.



Have you checked to see if there are any stored trouble codes in the PCM using a good OBDII scanner? I believe you can also check for codes by turning the ignition key ON-OFF-ON-OFF-ON (leave ON but do not attempt to start the engine) within 3 seconds. Immediately watch the check engine light as it'll flash any stored trouble codes as follows:



Each code will have two digits. The check engine light will blink the first digit then pause and blink the second digit. For example, trouble code 23 would be blink, blink, PAUSE, blink, blink, blink. The check engine light will display all stored codes one after the other, then end with blinking code 55 signaling the end. Please report back here if you find any trouble codes.



After you retrieve any stored trouble codes, you might also want try resetting the PCM by disconnecting the negative battery cables and briefly turning the ignition key to the START position. That will erase the PCM's memory of any learned parameters. It's a long shot at curing the problems you're decribing, but can't hurt anything.



Regards,



John L.

 

[Evest]

I had it scanned a week or so ago and no codes. But I just tried the on off on off on and it through code 12 and 33

 

[Evest]

I'm at the office right now. I was out in the shop messing with my truck and helping the boss take the transmission off our 1 ton. He just took it to a transmission guy. Anyway my phone died and I have it plugged in the office. I just came in to check my phone and e-mail. ... ... My book is at home. Do you know what code 12 and 33 r for? ... . As far as I knew untill now it wasnt throwing codes. I didn't know about checking codes this way.

 

[Moe]

EVEST. Sorry about my post earlier, I didnt look to see what year you had. However code 12 is battery was disconnected in the last 50 key-ons. It will clear itself. Code 33 is open or shorted condition in a/c clutch relay circuit. Hope this helps, Moe

 

[Evest]

Thanks Moe. I was just looking into that. I've disconnected the battery many time resently so that explains that. The clutch on the A/C compressor is broken and I have much more pressing issues so I unplugged the relay for it since its not working anyway. Not to mention its cold and I don't need the A/C right now. That kinda sucks I was hoping the codes where gonna help.

 

[JLandry]

Does the 1994 have a vehicle speed sensor in the rear differential? I don't have a wiring diagram for that early a model.



John L.

 

[Evest]

Yes it does and I replaced it already. Someone said something about it having to be clocked?

 

[JLandry]

Maybe time to try another (possibly rebuilt) PCM???



Do you know anyone with another 1994 you can borrow the PCM from to try?



John L.